Macrobenthos play an important role in aquatic ecosystems because they mineralize, promote, and mix the oxygen flux into the sediment, which recycles the organic matter. Sampling of macrobenthos populations for this study was carried out in the supratidal, mid tidal, low tidal, and subtidal regions of the Dayyer, Ouli, and Kangan stations in the Persian Gulf during both cold and warm seasons. Water parameters such as the temperature, salinity, pH, turbidity, and electrical conductivity were assessed, and were indicative of moderate water quality. Representatives of a total of 31 taxonomic families were identified during both seasons, of which 59 were identified to genus and species. The highest average number of species was observed in the low tidal region of Kangan in the warm season at 16.6 ± 1.2 species, and the lowest number was observed in the supratidal regions of Ouli and Kangan in the cold season at 6.6±2 species. The species diversity, as calculated using the Shannon–Wiener Index (H’), showed a significant difference between sampling seasons and sampling stations, as well as pollution level at the beaches. The species diversity index in Ouli, Dayyer, and Kangan stations also differed between the seasons. In both seasons, the Kangan station showed the highest species diversity while the Dayyer station showed the lowest. These results reveal a rich species diversity of macrobenthos and good water quality at the three beaches in the Persian Gulf. Re-assessment of species diversity during an environmental impact assessment prior to urban development should be further conducted to ensure that the

community is not significantly affected and the ecosystem remains intact.